package collection;

import java.util.ArrayList;
import java.util.Collection;

public class  CollectionDemo {
    public static void main(String[] args) {
        Collection c=new ArrayList();
        c.add(new Point(1,2));
        c.add(new Point(3,4));
        c.add(new Point(5,6));
        c.add(new Point(7,8));
        c.add(new Point(9,0));
        c.add(new Point(1,2));
        System.out.println(c);//[(1,2), (3,4), (5,6), (7,8), (9,0)]

        Point p=new Point(1,2);
        //比较的是给定元素p是否与当前集合存在equals()比较为true的情况
        //所以一般要重写equals()
        boolean contains= c.contains(p);
        System.out.println("contains判断为:"+contains);//true

        //boolean remove(Object o)-------一般不接收boolean结果
        //从当前集合中删除给定元素o的equals()比较为true的元素
        //若存在重复,只删除一次
        c.remove(p);
        System.out.println(c);

        //集合是存放元素的引用
        Collection cc=new ArrayList();
        Point pp=new Point(1,2);
        cc.add(pp);//将pp添加到集合cc中
        System.out.println(pp);
        System.out.println(cc);

        pp.setX(100);
        System.out.println(pp);
        System.out.println(cc);




        /* Collection c=new ArrayList();
        c.add("one");
        c.add("two");
        c.add("three");
        c.add("four");
        c.add("five");
        //集合重写了Object中的toString()方法,返回格式如下:
        //[元素1.toString(), 元素2.toString(), 元素3.toString, ......]
        System.out.println(c);//[one, two, three, four, five]
        //查看元素个数
        System.out.println("size"+c.size());//5
        System.out.println("是否为空集:"+c.isEmpty());//false

        c.clear();//清空集合
        System.out.println("集合已清空");
        System.out.println(c);
        System.out.println("size"+c.size());
        System.out.println("是否为空集:"+c.isEmpty());//true*/
    }
}
